A data transfer control device issues a session key identifying an application running on a user terminal. Then the device specifies a first database as a transfer destination of data input into a common data field for the first and a second database and outputs the data to an application process together with a session key. The device then inputs the data in the common data field together with the session key from the application process and updates the first database. After that, the device retrieves and outputs the data requested by the application process from the updated first database.